Prior Art Statement
The following publications are representative of the most relevant prior art known to the Applicant at the time of filing the application:
______________________________________ U.S. Pat. Nos. ______________________________________ 2,292,024 August 4, 1942 D. F. Dreher 2,395,668 February 26, 1946 W. Kellgren et al 2,565,509 August 28, 1951 B. C. Marcin 2,882,183 April 14, 1959 H. M. Bond et al 4,169,184 September 25, 1979 J. Pufahl 4,199,645 April 22, 1980 Gunter Schwarz 4,232,489 November 11, 1980 E. J. Corvington et al ______________________________________
Various types of flexible sealant strips have been proposed that carry a pressure sensitive adhesive for attaching the strip to a surface to be protected. One such known weather resistant strip adapted for use between a base and decorative layer attached to an automotive body for example is shown in U.S. Pat. No. 4,169,184 wherein a body of open celled, high density, flexible urethane foam that is impregnated with a vulcanized polychloroprene elastomer to form a deformable base material is described, the base being coated on opposite sides with a pressure sensitive adhesive. The tape or strip may be dispensed in a roll form and is made to have a significant inherent resilience and flexibility yet is described as including an ability to withstand elongation. The tape is prepared to be non-absorbent and solvent resistant for use in areas where gasoline, oils and greases might cause problems.
U.S. Pat. No. 4,199,645 also shows a laminated adhesive strip having an elastic carrier layer coated on opposed sides with adhesive layers having different characteristics for adhesion to different types of surfaces.
a basic form of a flexible and deformable strip coated on both sides with a pressure sensitive adhesive is illustrated in U.S. Pat. No. 2,292,024. This teaching provides an adhesive mounting strip for use between objects having irregular or undulating surfaces to provide a more uniform adhesive bonding action.
The use of release strips in combination with rolled up tapes having pressure sensitive adhesive on both sides thereof is known and typical tapes of this type are illustrated in U.S. Pat. Nos. 2,395,668, 2,565,509 and 4,169,184 mentioned above.
U.S. Pat. No. 2,882,183 describes a silicone tape backing having a single layer of a silicone adhesive on one side to form an electrical insulation that can be wrapped around an exposed electrical connection and then heated after it is in place to weld the layers of tape together to produce a sealed electrical covering.
U.S. Pat. No. 4,232,489 shows a flat strip of plastic foam forming a core for a tape with a pressure sensitive adhesive on one side for attaching the tape to a bow of a greenhouse enclosure for example, the tape having a silicone coated kraft paper adhered to its other side that forms a relatively friction free support surface for a sheet of plastic material laid on the exposed silicone impregnated paper material.
Thus the known flexible tapes show various types of adhesive strip structures adapted for insertion between elements to be associated together. However, none of these prior art teachings is directed to the problem of providing an effective substitute for a caulked seal between structural elements. It is the purpose of this invention to provide a sealant strip having various features of the known prior art combined together in a novel construction to satisfy the need for a flexible sealant strip adapted to mounting at the edges of abutting structural members to produce weather or moisture and air flow resistant seals along such joints to provide an effective seal.
None of the above described tapes is very well adapted to provide a substitute for a caulking such as is extruded conventionally into a joint to effect a waterproof seal for example, such caulking is usually applied after a structure has been erected. In this instance it is essential that the joint to be sealed to thoroughly cleaned before the caulking is forced into the joint and the sealant must be carefully applied through an extrusion nozzle moved along the joint. The proper quantity of sealant must be extruded to fill the joint and it must be applied in such a manner as to not interfere with the proper expansion and contraction of the seal in a manner to avoid breaking the seal. It is difficult to deliver the flowing sealant into the joint without some possibility of there being air holes, skips, and uneven application of the sealant in a manner to produce a uniform concave surface shape when it solidifies in place. In fact, the application of the usual caulking sealant in a joint after the structural parts have been assembled is so dependent on the skill of the operator that it should be considered more of an art than a science.